Alvin proportional dividers are used for dividing lines or circumference of circles into a number of equal parts and for enlarging and reducing lengths in different ratios. With a simple adjustment, reductions or enlargements can be transferred from original scale drawings with exacting accuracy (+ 0.1mm for any ratio). 10" divider with precise rack and pinion movement. Replaceable hardened steel needle points. Matte chrome finish resists wear and corrosion. Includes reference mark for golden section. Velvet lined case. Alvin 458 10" proportional dividers are quality-made in Germany.